If the hash table was created with an integer rehash size,
the result is an integer,
indicating that the rate of growth of the hash-table when rehashed
is intended to be additive;
otherwise,
the result is a float,
indicating that the rate of growth of the hash-table when rehashed
is intended to be multiplicative.
However, this value is only advice to the implementation;
the actual amount by which the hash-table will grow upon rehash is
implementation-dependent.